Graham Rice's New Plants Blog

Editor-in-Chief of the RHS Encyclopedia of Perennials; writer for a wide range of newspapers and magazines including The Garden and The Plantsman; member of the RHS Herbaceous Plant Committee and Floral Trials Committee; author of many books on plants and gardens.

Graham Rice's other blogs

In recent years we’ve seen quite a few new forms of that dependable summer shrub, Caryopteris – new forms which add attractive foliage to those valuable blue blooms.

Some of the new yellow-leaved forms of Caryopteris really are bright, but they’ve often proved less hardy than the plain green-leaved forms. ‘White Surprise’, a sport of the old favourite ‘Heavenly Blue’, seems just as hardy so there’s no worries about it coming through the winter. And the foliage really is bright, with clean white edges to the dark, slightly greyish green leaves, making the perfect background for the rich blue flowers.

Prune it back hard in the spring, as with all caryopteris, and you’re rewarded with a bright flush of dark grey-green foliage with its bright white edge. Then, from about August onwards, those clusters of blue flowers appear.

'White Surprise' reaches about 3ft high, and as wide, and makes a good container plant in any well-drained compost in a sunny place; in a sunny border, place it in the middle ground or towards the front. In prolonged hot and dry conditions, the edges of the leaves may burn a little so keep container plants watered and, when necessary, give border plants an occasional bucketful.

Caryopteris x clandonensis 'White Surprise' was discovered in Holland in 2005 by Jan Jacob Bos on his nursery at Wilp. One day he noticed a variegated shoot on a plant of ‘Heavenly Blue’, simple as that.

At the end of last year, on New Year’s Eve in fact, I highlighted some perennials to watch for this year, some exciting newcomers to look out for in nurseries and garden centres in 2010. So, have they arrived, are they available yet? Over the next few weeks – interspersed with news of other new plants - I’ll be bringing you news of two that have certainly arrived, and two still mysteriously missing from our nurseries.

Let’s start with the digitalis with Digitalis ‘Goldcrest' (left and below, click to enlarge), created by David Tristram, one of our most thoughtful plant breeders. He also developed the breakthrough Helleborus Walberton’s Rosemary (‘Walhero’) that was so impressive just inside the main gate at Wisley back in the winter and spring.

‘Goldcrest' is the first hybrid between the relatively uncommon Digitalis obscura, with rusty or sometimes pink-tinted yellow flowers, and the more familiar primrose yellow flowered D. grandiflora. Digitalis obscura brings its rusty colouring to ‘Goldcrest’, but it’s a Mediterranean plant, from Spain, and appreciates sunny summers, warm winters and good drainage. By contrast, the larger flowered D. grandiflora grows in eastern Europe, and is more adaptable and much hardier.

In combining qualities from both parents, ‘Goldcrest’ has large honeyed gold coloured flowers on self-supporting upright stems, each flower speckled on the inside and with hints of red on the outside. It’s also sterile, and in never producing any seeds the plant responds with an unusually prolific display. Ideal in a large container where you can appreciate the intriguing colouring, it’s also big and bold enough for a sunny border.

Still not in nurseries: Leucanthemum ‘Banana Cream’ (left, click to enlarge) This yellow form of the familiar Shasta daisy is short and self-supporting, but not too dumpy, branches well and has rich yellow flowers that fade to pale yellow. I assure you it’s superb. But, as far as I can tell, there’s still no nursery is listing it. An opportunity for an enterprising nursery.

Yes, ‘Celebration’ is the first large flowered clematis with golden yellow leaves.

As you can see from the picture (click to enlarge), the leaves really are bright yellow. What’s more the edges of the leaves are lined in red and the stems are red too. So the plant looks amazing even before flowering begins.

Then, in May and June, the double flowers open. Each flower is about 6in/15cm across, white with a blue tint, and with a gold flush on the basal petals. Later in the season the blooming is repeated, this time with single flowers. Prune every year after the display of double flowers, the plants should reach a height of about 6-8ft/1.8-2.4m).

Having said all that, the foliage looks so colourful that I’d be tempted to prune it hard in spring, miss out on those early flowers and grow it specifically as a foliage plant. There would still be single flowers later. I’m looking forward to trying both approaches. Leaf colour is best in full sun and in soil which is not too rich; Sussex Plants, who introduced the plant, say “avoid overfeeding”.

‘Celebration’ is a gold-leaved sport of the nineteenth century variety ‘Jackmanii Alba’ which has green foliage and double flowers with a little less blue colouring. ‘Celebration’ was discovered back in 1993 by Fred Godfrey of Sussex Plants, so it’s taken many years to bring the plant to the point when it can be made available.

Three new heleniums will be unveiled this weekend when the Plant Heritage National Collection holds its annual open days at Special Perennials near Crewe. Two of the newcomers were raised in Germany and one in Cheshire, in their various ways all three represent significant steps forward.

National Collection holder Martin Blow told me about them.

“The first, ‘Gelbe Waltraut’ (top, click to enlarge), is a seedling from the old favourite ‘Waltraut’,” he explained, “and is a beautiful clear, pure yellow with a high quality flower with a solid circular outline. Gelbe is German for yellow. Flowering from late June into the autumn it only reaches about 2-21/2ft/60-75cm tall. The flowers are numerous and create a dome of colour above the leaves. The cone is light tan in colour and complements the petals admirably. It was raised by Hartmut Rieger at his wonderful collection of Heleniums in Germany.

“Also from Hartmut Rieger is ‘Oldenburg’ (right, click to enlarge), which arose as a chance seedling in his garden. It is unique in its pale orange colouration with deeper orange backs to the petals. The petals are curled at the edges giving a bicolor effect. About 5-6ft/1.5-1.8m tall, it makes a welcome addition to the back of the border flowering from early August through September.

"The last of the three is ‘Blanche Royale’, raised by Ray Clarke from Macclesfield in Cheshire who has also raised many Hemerocallis. ‘Blanche Royale’ (left, click to enlarge) is the result of deliberate crosses using many of the best varieties around at the moment. The plants are about 21/2-3ft/75-90cm tall and develop a mass of blooming stems - the plant was selected for its flower power. The petals have a deep yellow ground with streaks of warm rich red radiating from the brown cones. Flowering starts in mid July and continues through September.”

With their wonderful colouring and, in two cases, their relatively dwarf and manageable habit they all look very tempting.

All three will be unveiled to visitors to The National Collection of Helenium Cultivars at Special Perennials at Hankelow in Cheshire this coming weekend (14 & 15 August, 12-5pm) when orders can be placed for delivery next spring. Check the Special Perennials website for details and directions.

‘Big Ben’ is a breakthrough blackcurrant with many good qualities but one very special feature. The fruits are huge, far far larger than the fruits of other blackcurrants.

Most blackcurrant berries weigh in at about 1.1g, but the average weight for a ‘Big Ben’ berry is 2.9g – that’s almost three times the size. The result is that each mature plant can produce 4.5kg (10lb) of fruit ripening about eight to ten days before the well known ‘Ben Lomond’.

Mature bushes of ‘Big Ben’ develop a slightly arching habit – not because they’re weak, they’re not, the branches are strong but just grow that way. It makes the fruit easier to pick and allows the plants to be trained on wires more easily if that’s what you prefer.

Developed specially as a variety for eating fresh – most new blackcurrants are developed specifically for commercial juice production – the large fruits are shiny, with a strong skin and are relatively sweet. They’re ideal for eating fresh.

Also valuable is the fact that ‘Big Ben’ is resistant to both powdery mildew and leafspot so you won;t need to spray to control these diseases.

‘Big Ben’ blackcurrant was developed at the Scottish Crops Research Institute near Dundee. All their previous blackcurrants have been named for Scottish mountains - ‘Ben Lomond’, ‘Ben Hope’ etc – but the enormous berries of ‘Big Ben’ led to an adjustment to their naming theme this one time.

Since its introduction in the USA about ten years ago, Hosta ‘Blue Mouse Ears’ has become one of the most popular of small hostas and in the five years its been available in Britain, it’s captured our attention for many reasons.

It’s small and neat, not more than 6in/15cm high, so is ideal at the very front of a border or even in a container; the dainty, slightly cupped leaves are indeed just like mouse ears; their faintly rippled blue colouring is very distinct; and the prolific flowers, like lavender hyacinths, sit tightly on the mound of foliage. On top of that, because the texture of the leaf is so heavy, it’s one of the hostas least likely to be eaten by slugs.

‘Blue Mouse Ears’ is also a plant that has produced some lovely sports – spontaneous genetic mutations. This happens a lot in hostas, variegated forms being the most frequent to turn up.

‘Blue Mouse Ears’, itself a sport of ‘Blue Cadet, spawned ‘Green Mouse Ears’, with green leaves, and then ‘Royal Mouse Ears’ with its leaves speckled and streaked in cream and white. Then came ‘Frosted Mouse Ears’, with a broad white edge to the leaves, and ‘Holy Mouse Ears’, with a white splash and streaking in the centre of the leaf. These last two were both developed by Mark Zilis, author of The Hostapedia – probably the most comprehensive hosta book available.

Most of these were on show at the Bowden Hostas exhibits at various shows this summer along with the very latest in the series – ‘Snow Mouse’. ‘Snow Mouse’ features a bolder white central zone in each leaf yet retains the same heavy, slug-resistant texture. It would make a lovely specimen in a terracotta pot.